Detection of cavitation phenomenon in a centrifugal pump using audible sound

One of the sources of instability in a centrifugal pump is cavitation within the pump. Cavitation of a centrifugal pump is the result of insufficient net positive suction head (NPSH) and can occur within the entire range of operating conditions. Cavitation may cause three different and undesirable effects: (1) a drop in head-capacity and efficiency curves, (2) damage to the impeller by pitting and erosion, and (3) structure vibration and resulting noise. Therefore, the cavitation process must be prevented by all means. To prevent the onset of cavitation we have to detect the beginning of the cavitation process in the pump. To detect the beginning of the cavitation process, the emitted noise can be used, among other possibilities. Specifically, a noise spectra structure can be used to detect the beginning of cavitation and its development. Experiments have shown that there is a discrete frequency tone, at 147 Hz, which is strongly dependent on the cavitation process and its development. Therefore, noise spectra can also be used to determine the NPSH required or the critical value, representing the upper limit of the permissible pump operation without cavitation.

Noise as an indicator of cavitation in a centrifugal pump

Improving centrifugal pump efficiency by impeller trimming

Investigation of effect of pump rotational speed on performance and detection of cavitation within a centrifugal pump using vibration analysis

The continuously increasing industrial productivity has resulted in a great breakthrough in the field of maintenance on centrifugal pumps in order to ensure their optimum operation under different operating conditions. One of the important mechanisms that affect the steady and dynamic operation of a pump is cavitation, which appears in the low static pressure zone formed at the impeller entrance region. This paper investigates the inception and development of cavitation in three different impellers of a laboratory centrifugal pump with a Plexiglas casing, using flow visualization, vibration and acoustic emission measurements. The aim of this study is the development of an experimental tool that detects cavitation in different impellers and the further understanding of the effects of blade geometry in cavitation development. The results show that the geometrical characteristics of the impeller affect cavitation development and behavior, while an acoustic emission sensor and an accelerometer can be applied for successfully detecting the onset of this mechanism.

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Experimental analysis of cavitation in a centrifugal pump using acoustic emission, vibration measurements and flow visualization

Centrifugal and Rotary Pumps offers both professionals and students a concise reference detailing the design, performance, and principles of operation of the different pumps types defined by the Hydraulic Institute. From historical background to the latest trends and technological developments, the author focuses on information with real-world prac

Lev Nelik

Papers

Centrifugal & Rotary Pumps: Fundamentals With Applications